How to animate correctly a GSAP menu?

问题

Holla, I need to reset the animation when I close menu and open it again. How can I do that? Animation works only the first time when I open menu.

CSSPlugin.defaultTransformPerspective = 600;
TweenMax.staggerFrom('ul#menu li', 1.5, {rotationX:-90, transformOrigin:"50% 0%", ease:Elastic.easeOut}, 0.4);

Here is the code: http://codepen.io/hafsadanguir/pen/qOdaab.

Thanks for help!

回答1:

Is this the kind of result you were after?

JavaScript:

CSSPlugin.defaultTransformPerspective = 600;
var toggleMenu = $('.menu-toggle');
var logo = $('#logo');
var logotitle = $('#logotitle');
var listItems = $('ul#menu li');
var timeline = new TimelineMax({ paused: true, reversed: true });
timeline.fromTo([logo, logotitle], 0.6, { top: 300 }, { top: -50, ease: Power2.easeInOut });
timeline.staggerFromTo(listItems, 1.2, { autoAlpha: 0, rotationX: -90, transformOrigin: '50% 0%' }, { autoAlpha: 1, rotationX: 0, ease: Elastic.easeOut.config(1, 0.3) }, 0.1, 0.3);

toggleMenu.on('click', function() {
  $(this).toggleClass('on');
  timeline.reversed() ? timeline.play() : timeline.reverse();
});

A few things have changed so here are the details:

• First and foremost, I didn't see the need for the hidden class so I have removed it from my solution.
• Plus, the on class toggled on the .menu-section element seemed pretty unnecessary as well. I removed it, but kept the properties defined on the .menu-section CSS rule.
• On to the fun part, the JavaScript.
• You basically needed a TimelineMax to operate upon.
• Judging by the imports you had in the JavaScript settings panel, I am assuming that you have some idea of what TimelineMax (and TimelineLite) are all about. By in any case, TimelineLite is about building and managing sequences of TweenLite, TweenMax, TimelineLite, and/or TimelineMax instances and TimelineMax is an extension of TimelineLite, adding more power to it.
• So, what happens in the code is that a TimelineMax instance has been initialised, tweens have been added to it and then, upon clicking of the .menu-toggle button element, this timeline is either played or reversed.
• The line timeline.reversed() ? timeline.play() : timeline.reverse(); is basically a shortened, fancy version of an if condition and it comes to down to personal preference more than anything else, no performance gain or anything that I am aware of. In a normal if clause, it would have been written like this:
  • if (timeline.reversed()) { timeline.play(); } else { timeline.reverse(); }.
  • The condition that is being checked is .reversed() property of timeline. You would notice that while initialising new TimelineMax(...), I set reversed: true property on it. What it does is that after all the tweens are added to timeline, it would behave as if timeline was immediately reversed such that the orientation of the timeline had been flipped. Read more about it in the TimelineMax documentation link I shared above.
  • The .play() and .reverse() methods are pretty self-explanatory as they make the timeline go forwards or backwards respectively.
• That is about it.

Hope this helps.

来源：https://stackoverflow.com/questions/32441947/how-to-animate-correctly-a-gsap-menu